The Seismometer is an instrument designed to measure the motions of the ground. This includes seismic waves generated by earthquakes, nuclear explosions, and other seismic sources. Records of these activities allow seismologists to map the interior of the Earth, and locate and measure the size of the different sources.
There are also seismographs, which is sometimes used in place of the word seismometer. However, a seismograph is the older instrument in which the measuring and recording...